Allah Taala said in the Quranil Kareem
(016.068) And thy Lord taught the Bee to build its cells in hills, on trees, and in (men’s) habitations
Shia narrated that masoom imam said: “That was revealed about us. We are bee, our shias are hills, and the trees are our women from believers. And imams are bees and Ali is our master”.
Source: Rajab al Borsi in “500 ayah nazalat fi ameral momeneen” with reference to tafseer al Mizan, tafseer al-Qummi.